Here's a new twist ... As mentioned above, Windows Media Player does HDCD. I use a USB DAC to get that signal into my system. Jerry does sound good floating 8 feet above the speakers.
The Jerry Garcia box set is all HDCD, as are the live releases from the estate (of JG). The Dead were mentioned above as being in HDCD.
If you like the Cheese, Bill Nershi & Liza Oxnard - It's About Time (2001) is HDCD.
Neil Young - Live at Massey Hall 1971 is HDCD? What a clean sounding recording this is for a live show. I'm going to have to get that on CD.
I get a lot of my tunes off the newsgroups. Anyone else do that? If it sounds good enough I'll get a used copy.
Any bluegrass in HDCD? Let me know.